Rolls-Royce RB.163 Spey is a low-bypass turbofan family developed for civil and military aircraft, including the three-engine Hawker Siddeley HS121 Trident and British Phantom/Buccaneer applications. BAE Heritage documents Trident 1C with three Spey 505 engines, Trident 2E and 3B with three Spey 512 engines, and Trident 3B separate RB162-86 booster; the family boundary is distinct from the RB162 booster and later Rolls-Royce turbofans. EASA current E.064 certification material lists the Spey 500 series under Rolls-Royce Deutschland type-certificate authority; lifecycle remains unknown because certification context alone does not establish current production.